data property
Input only.
Arbitrary key/value payload, which must be UTF-8 encoded. The key should
not be a reserved word ("from", "message_type", or any word starting with
"google" or "gcm"). When sending payloads containing only data fields to
iOS devices, only normal priority ("apns-priority": "5"
) is allowed in
[ApnsConfig
](/docs/reference/fcm/rest/v1/projects.messages#apnsconfig).
Implementation
core.Map<core.String, core.String>? data;